Apparatus and method for allocating OVSF codes and I/Q channels for reducing peak-to-average power ratio in transmitting data via enhanced up-link dedicated channels in WCDMA systems

ABSTRACT

The present invention supposes a situation in which an Enhanced Uplink Dedicated transport Channel (EUDCH) is used in a Wideband Code Division Multiple Access (WCDMA) system. In a user equipment (UE), when physical channels for transmitting EUDCH data are transmitted in addition to existing physical channels, a Peak-to-Average Power Ratio (PAPR) of an uplink transport signal increases. The increase in PAPR depends upon Orthogonal Variable Spreading Factor (OVSF) codes allocated to the corresponding physical channels and in-phase/quadrature-phase (I/Q) channels. Therefore, the present invention proposes an apparatus and method for allocating optimum OVSF codes and I/Q channels to EUDCH-related physical channels in order to minimize an increase in PAPR due to EUDCH.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription when taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a diagram illustrating user equipments (UEs) performing uplinktransmission and a Node B;

FIG. 2 is a diagram illustrating information exchanged between a UE anda Node B to perform uplink transmission;

FIG. 3 is a diagram illustrating a tree structure for general OVSFcodes;

FIG. 4 is a diagram illustrating a transmitter structure of a UEaccording to an embodiment of the present invention; and

FIG. 5 is a diagram illustrating a PAPR comparison result betweenphysical channels according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) OBJECT OF THEINVENTION RELATED FIELD AND PRIOR ART OF THE INVENTION

The present invention relates generally to an asynchronous Wideband CodeDivision Multiple Access (WCDMA) communication system, and inparticular, to an apparatus and method for minimizing an increase inPeak-to-Average Power Ratio (PAPR) of a transmission signal during datatransmission through an Enhanced Uplink Dedicated transport Channel(EUDCH).

That is, the present invention proposes an optimal Orthogonal VariableSpreading Factor (OVSF) code and in-phase/quadrature-phase (I/Q) channelallocation apparatus and method for uplink physical channels for EUDCHservice.

Currently, an uplink of a WCDMA system includes a Dedicated PhysicalData Channel (DPDCH) and a Dedicated Physical Control Channel (DPCCH) astypical dedicated physical channels used to transmit user signals. TheDPDCH is a data transport channel over which user data such as voice andimage is transmitted, and the DPCCH is a control information transportchannel on which DPDCH frame format information and pilot informationfor DPDCH demodulation and power control are carried.

Recently, technology using a EUDCH which is an enhanced uplink data-onlytransport channel has been proposed to improve a rate and efficiency ofpacket data transmission in an uplink.

FIG. 1 is a diagram illustrating information exchanged between userequipments and a Node B to perform uplink transmission.

Referring to FIG. 1, UEs 110, 112, 114 and 116 transmit packet data withdifferent transmission power according to their distances from a Node B100. The UE 110 which is located in the longest distance from the Node B100 transmits packet data with the highest transmission power 120 forthe uplink channel, while the UE 114 which is located in the shortestdistance from the Node B transmits the packet data with the lowesttransmission power 124 for the uplink channel. In order to improveperformance of the mobile communication system, the Node B 100 canperform scheduling in such a manner that a level of the transmissionpower for the uplink channel should be in reverse proportion to the datarate. That is, the Node B allocates the lowest data rate to a UE havingthe highest transmission power for the uplink channel, and allocates thehighest data rate to a UE having the lowest transmission power for theuplink channel.

FIG. 2 is a diagram illustrating information exchanged between a UE anda Node B to perform uplink transmission. That is, FIG. 2 illustrates abasic procedure required between a Node B 200 and a UE 202 for packetdata transmission through a EUDCH.

Referring to FIG. 2, in step 210, a EUDCH is set up between the Node B200 and the UE 202. Step 210 includes a process oftransmitting/receiving messages through a dedicated transport channel.After step 210, the UE 202 transmits in step 212 information on adesired data rate and information indicating an uplink channel conditionto the Node B 200. The information indicating an uplink channelcondition includes transmission power of an uplink channel transmittedby the UE 202 and a transmission power margin of the UE 203.

The Node B 200 receiving the uplink channel transmission power canestimate a downlink channel condition by comparing the uplink channeltransmission power with reception power. That is, the Node B 200considers that an uplink channel condition is good if a differencebetween the uplink channel transmission power and the uplink channelreception power is small, and considers that the uplink channelcondition is bad if the difference between the transmission power andthe reception power is great. When the UE transmits transmission powermargin to estimate an uplink channel condition, the Node B 200 canestimate the uplink transmission power by subtracting the transmissionpower margin from the known possible maximum transmission power for theUE. The Node B 200 determines the possible maximum data rate for anuplink packet channel of the UE 202 using the estimated channelcondition of the UE 202 and information on a data rate required by theUE 202.

The determined possible maximum data rate is notified to the UE 202 instep 214. The UE 202 determines a data rate for transmission packet datawithin a range of the notified possible maximum data rate, and transmitsin step 216 the packet data to the Node B 200 at the determined datarate.

Herein, uplink physical channels supporting the EUDCH service include aDedicated Physical Data Channel (DPDCH), a Dedicated Physical ControlChannel (DPCCH), a High Speed Dedicated Physical Control Channel(HS-DPCCH) for HSDPA service, an Enhanced Dedicated Physical DataChannel (E-DPDCH) for the EUDCH service, and an Enhanced DedicatedPhysical Control Channel (E-DPCCH) for the EUDCH service.

That is, in step 216, the UE 202 transmits an E-DPCCH which is a controlchannel to provide frame format and channel coding information of theE-DPDCH channel, and transmits packet data through the E-DPDCH. Herein,the E-DPCCH can also be used for transmission of an uplink data raterequired by the UE 202 and transmission power margin, and transmissionof pilot information required by the Node B 200 for demodulation of theE-DPDCH.

If the UE 202 additionally transmits separate physical channels inaddition to the existing physical channels in order to transmit EUDCHpacket data as described above, the number of physical channelstransmitted in the uplink increases, causing an increase in apeak-to-average power ratio (PAPR) of an uplink transmission signal. Itis general that the PAPR increases higher as the number ofsimultaneously transmitted physical channels increases higher.

Because the increase in the PAPR may increase distortion of transmissionsignals and an allowed Adjacent Channel Leakage power Ratio (ACLR), aradio frequency (RF) power amplifier in a UE requires power back-offwhich reduces amplifier's input power to prevent the foregoing problem.If the UE performs power back-off, the power back-off results in areduction in reception power at a receiver in a Node B, causing anincrease in error rate of received data or a reduction in cell coverage.

Accordingly, in order to prevent the increase in PAPR, the UE intends totransmit the EUDCH over the existing physical channel such as a DPDCH ona time division basis, instead of transmitting the EUDCH on a separatephysical channel. However, the process of transmitting the EUDCH overthe existing physical channel on a time division basis causes anincrease in implementation complexity.

Taking the problem into consideration, a WCDMA system has proposed amethod for multiplying the physical channels by OVSF codes satisfyingmutual orthogonality before transmission in the uplink. The physicalchannels multiplied by the OVSF codes can be distinguished in a Node B.

FIG. 3 is a diagram illustrating a tree structure for OVSF codesgenerally used in a WCDMA system.

Referring to FIG. 3, the OVSF codes can be simply generated in acalculation process of Equation (1) to Equation (3).C_(ch,1,0)=1,  Equation (1) $\begin{matrix}{\begin{bmatrix}C_{{ch},2,0} \\C_{{ch},2,1}\end{bmatrix} = {\begin{bmatrix}C_{{ch},1,0} & C_{{ch},1,0} \\C_{{ch},1,0} & {- C_{{ch},1,0}}\end{bmatrix} = {\begin{bmatrix}1 & {\quad 1} \\1 & {- 1}\end{bmatrix}.}}} & {{Equation}\quad(2)} \\{\begin{bmatrix}C_{{ch},2^{({n + 1})},0} \\C_{{ch},2^{({n + 1})},1} \\C_{{ch},2^{({n + 1})},2} \\C_{{ch},2^{({n + 1})},3} \\\vdots \\C_{{ch},2^{({n + 1})},2^{({n + 1})},{- 2}} \\C_{{ch},2^{({n + 1})},2^{({n + 1})},{- 1}}\end{bmatrix} = {\left\lbrack {\begin{matrix}C_{{ch},2^{n},0} \\C_{{ch},2^{n},0} \\C_{{ch},2^{n},1} \\C_{{ch},2^{n},1} \\\vdots \\C_{{ch},2^{n},{2^{n} - 1}} \\C_{{ch},2^{n},{2^{n} - 1}}\end{matrix}\begin{matrix}C_{{ch},2^{n},0} \\C_{{ch},2^{n},0} \\C_{{ch},2^{n},1} \\C_{{ch},2^{n},1} \\\vdots \\C_{{ch},2^{n},{2^{n} - 1}} \\C_{{ch},2^{n},{2^{n} - 1}}\end{matrix}} \right\rbrack.}} & {{Equation}\quad(3)}\end{matrix}$

As illustrated in FIG. 3, the OVSF codes are characterized in thatorthogonality is secured between codes having the same spreading factor(SF). In addition, for two codes having different SF values, if a codehaving a larger SF value cannot be generated from a code having a lowerSF value using Equation (3), orthogonality is acquired between the twocodes.

A description thereof will be made below by way of example.

For SF=4, C_(ch,4,0)=(1,1,1,1) is orthogonal with C_(ch,2,1)=(1,−1) butis not orthogonal with C_(ch,2,0)=(1,1).

As another example, comparing SF=256 OVSF codes with theC_(ch,2,1)=(1,1), because OVSF codes with SF=0˜127 are generated fromthe C_(ch,2,1)=(1,1), orthogonality is not secured therebetween. Thatis, as a higher data rate is required, an OVSF code with a lower SFvalue is used, and when a plurality of physical channels aresimultaneously transmitted, the OVSF codes should be allocated such thatorthogonality should necessarily be secured therebetween.

Even though two physical channels use the same OVSF code, if they areseparately transmitted through an I channel and a Q channel of atransmitter, a receiver can separate the two physical channel signalswithout mutual interference and demodulate the separated physicalchannel signals, because the signals transmitted on the I channel andthe Q channel are carried by carriers having a 90′-phase difference.

As described above, an increase in uplink PAPR depends on the number ofphysical channels simultaneously transmitted in the uplink, a powerratio between physical channels, an OVSF code used for each physicalchannel, and I/Q channel allocation for each physical channel.

In the WCDMA system to which the EUDCH technology is applied, if E-DPCCHand E-DPDCH channels for transmission of EUDCH packet data aresimultaneously transmitted in addition to the uplink channels, the PAPRincreases undesirably.

[Substantial Matter of the Invention]

It is, therefore, an object of the present invention to provide a UE'stransmission apparatus and method for efficiently transmitting packetdata through an enhanced uplink in a mobile communication system.

It is another object of the present invention to provide an OVSF codeand I/Q channel allocation apparatus and method for minimizing anincrease in PAPR of an uplink transmission signal in a mobilecommunication system supporting an uplink.

It is further another object of the present invention to provide anapparatus and method for allocating I/Q channels and OVSF codes forE-DPDCHs and an E-DPCCH to minimize an increase in PAPR according topresence/absence of an HS-DPCCH and the number of codes for DPDCHs.

In accordance with one aspect of the present invention, to achieve theobjects of the present invention, there is provided a method fortransmitting packet data in a mobile communication system supportingtransmission of enhanced uplink packet data, the method including thesteps of: generating a dedicated physical control channel (DPCCH) usingan Orthogonal Variable Spreading Factor (OVSF) code (256, 0) and aquadrature-phase (Q) channel; generating a dedicated physical datachannel (DPDCH) using an OVSF code (SF_(DPDCH), SF_(DPDCH)/4) and anin-phase (I) channel, where SF_(DPDCH) denotes a spreading factor of theDPDCH; generating an E-DPCCH using an OVSF code (SF_(E-DPCCH), 1) andthe I channel, where SF_(E-DPCCH) denotes a spreading factor of an OVSFcode to be allocated to an E-DPCCH for supporting transmission ofenhanced uplink packet data; generating an E-DPDCH using an OVSF code(SF_(E-DPDCH), SF_(E-DPDCH)/2) and the Q channel, where SF_(E-DPDCH)denotes a spreading factor (SF) value of an OVSF code to be allocated toan E-DPDCH and the SF_(E-DPDCH) is larger than 4; forming one complexsymbol stream by summing up the generated I and Q channels andscrambling the complex symbol stream; and transmitting the scrambledcomplex symbol stream through an antenna.

In accordance with another aspect of the present invention, to achievethe objects of the present invention, there is provided a method fortransmitting uplink packet data in a mobile communication systemsupporting transmission of enhanced uplink packet data, the methodincluding the steps of: generating dedicated physical channels and adedicated physical control channel for supporting a high speed downlinkpacket service using Orthogonal Variable Spreading Factor (OVSF) codes;generating dedicated physical channels for transmission of enhanceduplink packet data using OVSF codes unused by the physical channels;forming one complex symbol stream by summing up an I channel and a Qchannel of the generated channels and scrambling the complex symbolstream; and transmitting the scrambled complex symbol stream through anantenna.

[Construction and Operation of the Invention]

Several preferred embodiments of the present invention will now bedescribed in detail with reference to the annexed drawings. In thefollowing description, a detailed description of known functions andconfigurations incorporated herein has been omitted for conciseness.

The present invention proposes an OVSF code and I/Q channel allocationmethod for minimizing an increase in PAPR of an uplink transmissionsignal in a WCDMA system supporting EUDCH data service. That is, thepresent invention proposes an OVSF code and I/Q channel allocationmethod optimized for the case where an E-DPCCH which is a controlchannel and an E-DPDCH which is a data channel, for transmission ofEUDCH packet data, are transmitted in addition to the existing physicalchannels. In order to increase a EUDCH data rate and minimize anincrease in PAPR, the present invention proposes an OVSF code and I/Qchannel allocation method for minimizing the PAPR increase whilemaintaining orthogonality between the existing DPCCH, DPDCH andHS-DPCCH.

In the existing Rel-5 WCDMA standard, OVSF code and I/Q channelallocation for an HS-DPCCH channel is achieved so as to reduce a PAPRconsidering the maximum number of transmittable DPDCHs, determinedduring setup of a radio link between a UE and a Node B.

Therefore, OVSF code and I/Q channel allocation for an E-DPDCH and anE-DPCCH, proposed in the present invention, is achieved considering themaximum number of DPDCHs transmittable in the radio link andtransmission/non-transmission of an HS-DPCCH, for the Rel-5 physicalchannels. In the EUDCH service, several E-DPDCH physical channels can besimultaneously transmitted because they support high-data ratetransmission. However, it is generally sufficient that a single E-DPCCH,which is a physical control channel, is transmitted.

That is, in order to reduce a PAPR increase of an uplink transmissionsignal, the present invention supports a EUDCH considering backwardcompatibility with the existing WCDMA system. The reason is becauseserious problems may occur in initial call setup or handover processeswhen Node Bs are inconsistent with each other in terms of a version dueto incompatibility for DPDCH and DPCCH standard.

In other words, the present invention proposes an OVSF code and I/Qchannel allocation method optimized to minimize the PAPR increase forEUDCH-related physical channels while maintaining the existing Rel-5WCDMA standard for the DPDCH and the DPCCH which are core uplinkphysical channels.

First, assuming that the existing uplink channels such as a DPCCH, aDPDCH and an HS-DPCCH undergo OVSF code and I/Q channel allocation asdefined in the current standard in an OVSF code and I/Q channelallocation method by maintaining full compatibility with the existingRel-5 WCDMA system, the present invention proposes an OVSF code and I/Qchannel allocation method optimized for the case where an E-DPCCH and anE-DPDCH which are physical channels for transmission of EUDCH packetdata are additionally transmitted on that assumption.

Second, the case where compatibility with the HS-DPCCH is partially lostwhile compatibility with the existing DPDCH and DPCCH is maintained willbe taken into consideration. In the current Rel-5 WCDMA standard, if themaximum number of transmittable DPDCHs is one, the HS-DPCCH istransmitted on a Q channel using an OVSF code (256, 64). In this case,because an E-DPDCH cannot use an OVSF code (4, 1) on the Q channel, amaximum EUDCH data rate is limited accordingly. In order to solve theproblem, the present invention proposes a code allocation rule for theHS-DPCCH, E-DPCCH and E-DPDCH so as to enable the E-DPDCH to use theOVSF code (4, 1) on the Q channel and reduce a PAPR of UE's transmissionsignal.

Third, in a Rel-6 standard, even a EUDCH stand-alone case in which noDPDCH is transmitted and only the E-DPDCH is transmitted in the uplinkis taken into consideration. Therefore, the present invention presentsan OVSF code and I/Q channel allocation rule for the HS-DPCCH for theEUDCH stand-alone case.

In the foregoing methods, I/Q channel and OVSF code allocation for theHS-DPCCH depends on the maximum number of transmittable DPDCH channels,and the number of E-DPDCH channels does not affect the allocation rulefor the HS-DPCCH. This is because the E-DPDCH is not always transmitted,but transmitted only when there is data in a EUDCH data buffer of a UE.Therefore, in terms of a PAPR, it is preferable to define an OVSF codeand I/Q channel allocation rule for the HS-DPCCH considering only theDPDCH according to the current standard.

FIG. 4 is a diagram illustrating a transmitter structure of a UEaccording to an embodiment of the present invention.

1. DPCCH

A DPCCH is allocated an OVSF code (256, 0) on a Q channel according tothe existing Rel-99 and Rel-5 channel allocation rules. The (256, 0) isequal to an OVSF code C_(ch,256,0) illustrated in FIG. 3. That is, inFIG. 4, the DPCCH is multiplied by the OVSF code C_(ch,256,0) forspreading after being BPSK-modulated, and then multiplied by atransmission gain β_(c). The β_(c) is set by a network according to arate or a required quality-of-service level of data transmitted by a UE.

The DPCCH signal is added to other channel signals transmitted through aQ channel, multiplied by a scrambling code S_(dpch,n), and thentransmitted via an antenna through a transmission pulse forming filterand an RF stage.

2. DPDCH

According to the channel allocation rule defined in the existingstandard, if an SF value of a DPDCH is denoted by SF_(DPDCH), the DPDCHis spread by an OVSF code (SF_(DPDCH), SF_(DPDCH)/4) on an I channel. InFIG. 4, c_(d) denotes an OVSF code for a DPDCH. In the presentinvention, it is assumed that when physical channels related to theEUDCH service are transmitted together with the DPDCH, only a maximum ofone DPDCH channel is transmitted.

3. HS-DPCCH

Also, this follows the existing Rel-5 standard and is transmitted onlywhen HSDPA service is achieved in a downlink. As can be seen in FIG. 4,when only one DPDCH is transmitted in the uplink, an HS-DPCCH is spreadby an OVSF code (256, 64) on a Q channel.

4. E-DPCCH

An E-DPCCH, a physical control channel for EUDCH service, transmits abuffer state of a UE, or transmits uplink transmission power, uplinktransmission power margin, and channel state information (CSI), whichare needed by a Node B to estimate an uplink channel condition. TheE-DPCCH transmits a Transport Format and Resource Indicator (E-TFRI) forEUDCH service transmitted over the E-DPDCH.

If an SF value of an E-DPCCH is denoted by SF_(E-DPCCH), the E-DPCCH isspread by an OVSF code (SF_(E-DPCCH), 1) on an I channel. Herein, OVSFcodes and I/Q channels are allocated to the E-DPCCH in a free way.

In an alternative method, the E-DPCCH uses an OVSF code(SF_(E-DPCCH), 1) on a Q channel, unlike the DPCCH transmitted using anOVSF code (256, 1) on an I channel.

In another alternative method, the E-DPCCH is allocated to a Q channelwhen no DPDCH is set up and an HS-DPCCH is set up. In this case, an OVSFcode (SF_(E-DPCCH), 1) or (SF_(E-DPCCH), SF_(E-DPCCH)/8) is suitable forthe E-DPCCH.

In further another alternative method, when no DPDCH is set up, theE-DPCCH can be allocated to the Q channel regardless of setup/non-setupof the HS-DPCCH. In this case, an OVSF code (SF_(E-DPCCH), 1) or(SF_(E-DPCCH), SF_(E-DPCCH)/8) is suitable for the E-DPCCH.

Such a rule is always available regardless oftransmission/non-transmission of the HS-DPCCH and the number of E-DPDCHchannels. In this case, 8, 16, 32, 64, 128 and 256 are available for theSF_(E-DPCCH), and an SF_(E-DPCCH) value to be actually used isdetermined considering the amount of information to be transmitted overthe E-DPCCH.

In the case where no DPDCH is set up and an HS-DPCCH is set up for an Ichannel (256, 1), even if SF_(E-DPCCH)=256, the E-DPCCH cannot beallocated (SF_(E-DPCCH), 1). Therefore, the E-DPCCH cannot be allocatedfor I channels (SF_(E-DPCCH), 2) to (SF_(E-DPCCH), SF_(E-DPCCH)/8). Thatis, allocating the E-DPCCH for the I channels (SF_(E-DPCCH), 2) to(SF_(E-DPCCH), SF_(E-DPCCH)/8) is most efficient in achieving a low PARvalue. Herein, 32, 64, 128 and 256 are available for the SF_(E-DPCCH).

Referring to FIG. 4, a EUDCH transmission controller 402 transmitscontrol information through the E-DPCCH, which is needed by a Node B toreceive an E-DPDCH. In FIG. 4, c_(ch,SF,1) denotes an OVSF code for theE-DPCCH, and is multiplied by a transmission symbol so that thecorresponding channel should be orthogonal with other physical channels.In addition, a transmission gain β_(E-DPCCH) of the E-DPCCH, like thoseof other physical channels, is set according to a rate or a requiredquality-of-service level of data transmitted by a UE.

5. E-DPDCH

An E-DPDCH, a dedicated physical data channel for the EUDCH service,transmits EUDCH packet data using a data rate determined based onscheduling information provided from the Node B. The E-DPDCH supportsnot only BPSK but also QPSK and 8PSK in order to increase a data ratewhile maintaining the number of simultaneously transmitted spreadingcodes.

Referring back to FIG. 4, the E-DPDCH simultaneously transmits twochannels of an E-DPDCH1 and an E-DPDCH2, by way of example. Herein, itis obvious that the number of E-DPDCH physical channels in use dependson a transfer rate of EUDCH packet data. In addition, the EUDCHtransmission controller 402 determines the number of simultaneouslytransmitted E-DPDCH channels and an SF value.

In other words; when a data rate is low, an E-DPDCH is spread with anOVSF code having a relatively large SF value so that it can betransmitted with one E-DPDCH. However, when a data rate is high, anSF_(E-DPCCH) value is set to 4 or 2 so that EUDCH packet data istransmitted through one or two E-DPDCH channels.

That is, a EUDCH packet transmitter 404 transmits EUDCH transmissiondata through an E-DPDCH1 under the control of the EUDCH transmissioncontroller 402. Alternatively, even the E-DPDCH2 is allocated for thetransmission when necessary. A EUDCH data buffer 400 is a buffer forstoring EUDCH data to be transmitted. The EUDCH data to be transmittedthrough the E-DPDCH channels is delivered to the EUDCH packettransmitter 404 under the control of the EUDCH transmission controller402.

A description will now be made of methods for allocating OVSF codes andI/Q channels for E-DPDCHs according to several embodiments of thepresent invention.

First Embodiment

A first embodiment proposes methods for allocating OVSF codes and I/Qchannels for the E-DPDCHs without considering DPDCHs. The proposedmethods can reduce a PAPR by appropriately adjusting the minimumspreading gain value for E-DPDCHs and the number of transmissionchannels according to a EUDCH data rate. Herein, for convenience ofdescription, the methods will be divided into Method A, Method B andMethod C considering an SF_(E-DPDCH) set based on a data rate.

Method A corresponds to a case where an SF_(E-DPDCH) for E-DPDCHs is setto 4 or larger.

1. One E-DPDCH Channel Transmitted

An E-DPDCH1 transmits EUDCH transmission symbols through a Q channelusing an OVSF code (SF_(E-DPDCH), SF_(E-DPDCH)/2). Herein, 4, 8, 16, 32,64, 128 and 256 are available for the SF_(E-DPDCH). In FIG. 4, c_(ed1)denotes an OVSF code used for the E-DPDCH1. The E-DPDCH1 allocated anOVSF code in this way satisfies orthogonality with other physicalchannels. That is, compared with a DPDCH transmitted on an I channel,the E-DPDCH1 can reduce its PAPR as it is transmitted on the Q channel.

2. Two E-DPDCH Channels Transmitted

When an SF_(E-DPDCH) for an E-DPDCH1 and an E-DPDCH2 is 4, the E-DPDCH1and the E-DPDCH2 are spread with an OVSF code (4, 2) and thensimultaneously transmitted through a Q channel and an I channel,respectively. That is, the E-DPDCH1 is allocated to the Q channel, andthe E-DPDCH2 is allocated to the I channel. Herein, the EUDCH packetdata is transmitted with a modulation scheme having a 4^(th) order orhigher, such as QPSK, 8PSK and 16QAM.

For example, when QPSK modulation is used, symbols transmitted throughthe E-DPDCH1 and the E-DPDCH2 are transmitted in four possiblecombinations of (±1, ±1), and when 8PSK is used, symbols transmittedthrough the E-DPDCH1 and the E-DPDCH2 are transmitted in eight possiblecombinations of (±{square root}{square root over (2)},0), (0,±{squareroot}{square root over (2)}) and (±1, ±1).

If a desired EUDCH data rate cannot be achieved even though the twochannels of the E-DPDCH1 and the E-DPDCH 2 are simultaneouslytransmitted using the SF_(E-DPDCH)=4, it is possible to enabletransmission at a higher data rate by setting the SF_(E-DPDCH) to 2.That is, if an SF_(E-DPDCH) for the E-DPDCH1 and the E-DPDCH2 is 2, theE-DPDCH1 and the E-DPDCH2 are spread with an OVSF code (2, 1) and thensimultaneously transmitted on a Q channel and an I channel,respectively.

When it is necessary to transmit several E-DPDCH physical channels inthis way, it is possible to remarkably reduce a PAPR by halving thenumber of E-DPDCH channels being transmitted, as compared with the casewhere the minimum spreading gain is 4.

Method B is similar to Method A described above, but allocates OVSFcodes such that when only an E-DPDCH1 is transmitted, SF_(E-DPDCH) isset to a minimum of 2.

1. One E-DPDCH Channel Transmitted

When only the E-DPDCH1 is transmitted, 2, 4, 8, 16, 32, 64, 128 and 256are available for the SF_(E-DPDCH). The E-DPDCH1 is allocated to a Qchannel using an OVSF code (SF_(E-DPDCH), SF_(E-DPDCH)/2).

2. Two E-DPDCH Channels Transmitted

The E-DPDCH1 and the E-DPDCH2 are spread with an OVSF code (2, 1) andthen simultaneously transmitted on a Q channel and an I channel,respectively. In this case, EUDCH packet data is transmitted with amodulation scheme having a 4^(th) order or higher, such as QPSK, 8PSKand 16QAM.

Method C is similar to Method A described above, but allocates OVSFcodes such that SF_(E-DPDCH) for the E-DPDCH 1 is set to 2 andSF_(E-DPDCH) for the E-DPDCH2 is set to 4, if a desired EUDCH data ratecannot be achieved even though the two channels of the E-DPDCH1 and theE-DPDCH 2 are simultaneously transmitted using the SF_(E-DPDCH)=4.

1. One E-DPDCH Channel Transmitted

When an SF_(E-DPDCH) for E-DPDCHs is 4 or larger, EUDCH transmissionsymbols are transmitted through a Q channel using an OVSF code(SF_(E-DPDCH), SF_(E-DPDCH)/2). Herein, 4, 8, 16, 32, 64, 128 and 256are available for the SF_(E-DPCCH).

2. Two E-DPDCH Channels Transmitted

When an SF_(E-DPDCH) for the E-DPDCH1 and the E-DPDCH2 is 4, theE-DPDCH1 and the E-DPDCH2 are spread with an OVSF code (4, 2) and thensimultaneously transmitted through a Q channel and an I channel,respectively. If a desired EUDCH data rate cannot be achieved eventhough the two channels of the E-DPDCH1 and the E-DPDCH 2 aresimultaneously transmitted, an SF_(E-DPDCH) for the E-DPDCH1 and anSF_(E-DPDCH) for the E-DPDCH2 are set to different values.

That is, as an SF_(E-DPDCH) for the E-DPDCH1 is set to 2 and anSF_(E-DPDCH) for the E-DPDCH2 is set to 4, data carried on therespective channels independently undergoes BPSK modulation before beingtransmitted. Therefore, symbols transmitted on the E-DPDCH1 and theE-DPDCH2 are spread with OVSF codes (2, 1) and (4, 2) on a Q channel andan I channel, respectively, before being transmitted.

In addition, when a data rate cannot be achieved in the foregoingmanner, the SF_(E-DPDCH) for the E-DPDCH1 is set to 2 and theSF_(E-DPDCH) for the E-DPDCH2 is set to 2 for transmission. That is, theE-DPDCH2 and the E-DPDCH1 are spread with an OVSF code (2, 1) and thensimultaneously transmitted on the I channel and the Q channel,respectively. In this case, the EUDCH packet data can be transmittedwith a modulation scheme having a 4^(th) order or higher, such as QPSK,8PSK and 16QAM.

Method D is a method for allocating an OVSF code (4, 1) to an additionalE-DPDCH to increase a EUDCH packet data rate when a DPDCH and anHS-DPCCH are not transmitted or when an OVSF code generated from an OVSFcode (4, 0) is used even though the HS-DPCCH is transmitted. This isbecause the HS-DPCCH is transmitted only for the HSDPA service. Inaddition, this is because when there is no data to be transmitted over aDPDCH, the DPDCH is occasionally used only for transmission of signalinginformation and may not be transmitted for the other time. In thepost-Rel-5 WCDMA standard, there is a possible case where the DPDCH isnot set up and only the E-DPDCH is set up.

1. Two or Less E-DPDCH Channels Transmitted

The foregoing Method A, Method B, or Method C can be used.

2. Three E-DPDCH Channels Transmitted

When an HS-DPCCH is not transmitted, an E-DPDCH3 channel is transmittedthrough a Q channel using an OVSF code (4, 1).

Alternatively, when the HS-DPCCH is transmitted and the DPDCH is nottransmitted, the E-DPDCH3 channel is transmitted through an I channelusing the OVSF code (4, 1).

3. Four or More E-DPDCH Channels Transmitted

The I channel and the Q channel both use the OVSF code (4, 1) fortransmission. This is applied when the OVSF code (4, 1) is not used bythe DPDCH and the HS-DPCCH.

In other words, when both of the HS-DPCCH and the DPDCH are nottransmitted, third and fourth E-DPDCH channels are transmitted throughthe I channel and the Q channel using the OVSF code (4, 1),respectively. Even when the DPDCH is not set up and the HS-DPCCH istransmitted using an OVSF code generated from the OVSF code (4, 0), theOVSF code (4, 1) is never used in the I and Q channels. Therefore, it ispossible to transmit the third and fourth E-DPDCH channels on the I/Qchannels using the OVSF code (4, 1).

Second Embodiment

A second embodiment proposes methods for applying an OVSF code and I/Qchannel allocation rule for the E-DPDCH in a different way consideringsetup/non-setup of an HS-DPCCH.

The second embodiment provides a method for first allocating an E-DPDCHto an I channel when the HS-DPCCH is set for an OVSF code (256, 64) in aQ channel, thereby reducing a PAPR. The second embodiment isadvantageous in that it can remarkably reduce a PAPR when an HS-DPCCHhas higher power than that of a DPDCH as a UE is located in the vicinityof a cell boundary.

When the HS-DPCCH is not set up, OVSF codes are allocated in thefollowing method.

1. One E-DPDCH Transmitted

An E-DPDCH transmits EUDCH transmission symbols on a Q channel using anOVSF code (SF_(E-DPDCH), SF_(E-DPDCH)/4). Herein, 4, 8, 16, 32, 64, 128,256 and 512 are available for the SF_(E-DPDCH).

If a EUDCH data rate cannot be fully achieved even though theSF_(E-DPDCH)=4 is used, the E-DPDCH uses on the Q channel an OVSF code(2, 1) with SF_(E-DPDCH)=2 instead of its OVSF code (SF_(E-DPDCH),SF_(E-DPDCH)/4).

2. Two E-DPDCHs Transmitted

When an SF_(E-DPDCH) for E-DPDCHs is set to 2, an E-DPDCH1 istransmitted on a Q channel using an OVSF code (2, 1), and an E-DPDCH2 istransmitted on an I channel using an OVSF code (2, 1).

Alternatively, the E-DPDCH1 is transmitted on the Q channel using anOVSF code (2, 1), and the E-DPDCH2 is transmitted on the I channel usingan OVSF code (4, 2). In this case, if a desired EUDCH data rate cannotbe achieved, an SF_(E-DPDCH) for the E-DPDCH2 is set to 2 and an OVSFcode (2, 1) is used instead of the OVSF code (4, 2) for transmission ofthe E-DPDCH2.

3. Three E-DPDCHs Transmitted

When an E-DPDCH 1 is transmitted on a Q channel using an OVSF code(2, 1) and an E-DPDCH2 is transmitted on an I channel using an OVSF code(2, 1), an E-DPDCH3 is transmitted on the Q channel using an OVSF code(4, 1).

4. Fourth E-DPDCHs Transmitted

An E-DPDCH4 is transmitted on an I channel using an OVSF code (4, 1).

Herein, the case where an OVSF code (4, 1) can be used on both the Ichannel and the Q channel corresponds to the case where the OVSF code(4, 1) is unused by a DPDCH and an HS-DPCCH. That is, in the case whereno DPDCH is set up, or in the case where a DPDCH is equal to an E-DPDCHin radio frame length even though the DPDCH is set up, an E-DPDCH4 istransmitted on an I channel using an OVSF code (4, 1) in addition to theE-DPDCH1, E-DPDCH2, and E-DPDCH3 in a transmission time interval (TTI)for which the DPDCH is not transmitted.

However, when an HS-DPCCH is set for (Q, 256, 64), an OVSF codeallocation method is as follows.

1. One E-DPDCH Transmitted

An E-DPDCH1 transmits EUDCH transmission symbols on an I channel usingan OVSF code (SF_(E-DPDCH), SF_(E-DPDCH)/2). Herein, 2, 4, 8, 16, 32,64, 128, 256 and 512 are available for the SF_(E-DPDCH).

2. Two E-DPDCHs Transmitted

An E-DPDCH1 is transmitted on an I channel using an OVSF code (2, 1),and an E-DPDCH2 is also transmitted on a Q channel using an OVSF code(2, 1).

Third Embodiment

A third embodiment uses the same OVSF code allocation method as that ofthe second embodiment when an HS-DPCCH is not set up. However, the thirdembodiment is characterized in that it first allocates an E-DPDCH to a Qchannel instead of an I channel on which the HS-DPCCH is set for (Q,256, 64).

When the HS-DPCCH is not set up, the third embodiment uses the same OVSFcode allocation method as that of the second embodiment.

However, when the HS-DPCCH is set for (Q, 256, 64), the following OVSFcode allocation method is used.

1. One E-DPDCH Transmitted

An E-DPDCH1 uses (SF_(E-DPDCH), SF_(E-DPDCH)/2) on a Q channel, and 2,4, 8, 16, 32, 64, 128, 256 and 512 are available for the SF_(E-DPDCH).

2. Two E-DPDCHs Transmitted

When an SF_(E-DPDCH) for E-DPDCHs is set to 2, an E-DPDCH1 istransmitted on a Q channel using an OVSF code (2, 1), and an E-DPDCH2 istransmitted on an I channel using an OVSF code (2, 1).

Alternatively, the E-DPDCH1 is transmitted on the Q channel using anOVSF code (2, 1), and the E-DPDCH2 is transmitted on the I channel usingan OVSF code (4, 2). In this case, if a desired EUDCH data rate cannotbe achieved, an SF_(E-DPDCH) for the E-DPDCH2 is set to 2 and an OVSFcode (2, 1) is used instead of the OVSF code (4, 2) for transmission ofthe E-DPDCH2.

3. Three E-DPDCHs Transmitted

In the case where no DPDCH is set up, or in the case where a DPDCH isequal to an E-DPDCH in radio frame length even though the DPDCH is setup, an E-DPDCH3 is transmitted on a Q channel using an OVSF code (4, 1)in addition to the E-DPDCH1 and E-DPDCH2 transmitted on I and Q channelsusing an OVSF code (2, 1), in a TTI for which the DPDCH is nottransmitted on the I channel.

Fourth Embodiment

A fourth embodiment proposes a method for reducing a PAPR andefficiently using OVSF codes for the case where no DPDCH is set up orthe case where an E-DPDCH is equal to a DPDCH, even if it is set up, inradio frame length, in the case where an HS-DPCCH is set for an OVSFcode (256, 64) on a Q channel. An I/Q channel and OVSF code allocationmethod used for E-DPDCHs varies according to presence/absence of DPDCHstransmitted in the current TTI.

1. One E-DPDCH Transmitted

When DPDCHs are transmitted in the current TTI, an E-DPDCH1 uses(SF_(E-DPDCH), SF_(E-DPDCH)/2) on a Q channel, and 2, 4, 8, 16, 32, 64,128, 256 and 512 are available for the SF_(E-DPDCH).

However, when no DPDCH is transmitted in the current TTI, an OVSF code(SF_(E-DPDCH), SF_(E-DPDCH)/4) is used on an I channel, and 4, 8, 16,32, 64, 128, 256 and 512 are available for the SF_(E-DPDCH). In thiscase, in order to further increase a EUDCH data rate, the E-DPDCH istransmitted using an OVSF code (2, 1) instead of the OVSF code(SF_(E-DPDCH), SF_(E-DPDCH)/4).

2. Two E-DPDCHs Transmitted

When an SF_(E-DPDCH) for E-DPDCHs is set to 2, an E-DPDCH1 istransmitted on a Q channel using an OVSF code (2, 1), and an E-DPDCH2 istransmitted on an I channel using an OVSF code (2, 1).

Alternatively, the E-DPDCH1 is transmitted on the Q channel using anOVSF code (2, 1), and the E-DPDCH2 is transmitted on the I channel usingan OVSF code (4, 2). In this case, if a desired EUDCH data rate cannotbe achieved, an SF_(E-DPDCH) for the E-DPDCH2 is set to 2 and an OVSFcode (2, 1) is used instead of the OVSF code (4, 2) for transmission ofthe E-DPDCH2.

3. Three E-DPDCHs Transmitted

In addition to the E-DPDCH1 and the E-DPDCH2 transmitted on the Q and Ichannels using the OVSF code (2, 1), an E-DPDCH is transmitted on the Ichannel using an OVSF code (4, 1) when no DPDCH is transmitted in thecurrent TTI.

Fifth Embodiment

A fifth embodiment proposes a method for allocating E-DPDCHs when noDPDCH is set up. For the E-DPDCHs, the fifth embodiment has a basicconcept of allocating an E-DPDCH1 to opposite I/Q channels of the I/Qchannels on which an HS-DPDCH is transmitted, and can reduce a PAPR whena channel gain factor for the HS-DPCCH is high.

When the HS-DPCCH is not set up, an E-DPDCH allocation method is asfollows.

1. One E-DPDCH Transmitted

An E-DPDCH1 transmits EUDCH transmission symbols on an I channel usingan OVSF code (SF_(E-DPDCH), SF_(E-DPDCH)/4). Herein, 4, 8, 16, 32, 64,128, 256 and 512 are available for the SF_(E-DPDCH). In this case, if aEUDCH data rate cannot be fully achieved even though the SF_(E-DPDCH) isset to 4, the SF_(E-DPDCH) is set to 2 and the EUDCH transmissionsymbols are transmitted on the I channel using an OVSF code (2, 1)instead of the OVSF code (SF_(E-DPDCH), SF_(E-DPDCH)/4).

2. Two E-DPDCHs Transmitted

An E-DPDCH1 is transmitted on an I channel using an OVSF code (2, 1),and an E-DPDCH2 is transmitted on a Q channel using an OVSF code (2, 1).

3. Three or More E-DPDCHs Transmitted

In addition to the E-DPDCH1 and the E-DPDCH2, an E-DPDCH3 and anE-DPDCH4 transmit EUDCH transmission symbols on I and Q channels usingan OVSF code (4, 1).

However, when the DPDCH is not set up and an HS-DPCCH is set up, theHS-DPCCH is likely allocated for the I channel.

1. One E-DPDCH Transmitted

An E-DPDCH transmits EUDCH transmission symbols on a Q channel using anOVSF code (SF_(E-DPDCH), SF_(E-DPDCH)/4). Herein, 4, 8, 16, 32, 64, 128,256 and 512 are available for the SF_(E-DPDCH). If a EUDCH data ratecannot be fully achieved even though the SF_(E-DPDCH)=4 is used, the SFis set to 2 and the Q channel uses an OVSF code (2, 1).

2. Two E-DPDCHs Transmitted

An E-DPDCH1 is transmitted on a Q channel using an OVSF code (2, 1), andan E-DPDCH2 is transmitted on an I channel using an OVSF code (2, 1).

3. Three or More E-DPDCHs Transmitted

In addition to the E-DPDCH1 and the E-DPDCH2 transmitted on the Q and Ichannels using an OVSF code (2, 1), an E-DPDCH3 and an E-DPDCH4additionally transmit EUDCH transmission symbols on both the I and Qchannels using an OVSF code (4, 1).

Referring back to FIG. 4, the EUDCH transmission controller 402transmits UE's data buffer state and CSI, required for Node B'sscheduling control, to the Node B through the E-DPCCH. The EUDCHtransmission controller 402 determines an E-TFRI and transmits thedetermined E-TFRI to the Node B through the E-DPCCH. The E-TFRI isdetermined using a possible maximum data rate.

The EUDCH packet transmitter 404 receives packet data determined basedon the E-TFRI from the EUDCH data buffer 400. The received packet dataundergoes channel coding and modulation using the E-TFRI, and thentransmitted to the Node B through the E-DPDCH1 and E-DPDCH2 channelsaccording to an embodiment of the present invention.

Data on the DPDCH is spread at a chip rate using an OVSF code c_(d) in amultiplier 422, and multiplied by a channel gain c_(d) in a multiplier424. The DPDCH data multiplied by the channel gain β_(d) is input to asummer 426.

Control information on an E-DPCCH is spread in a multiplier 406 at achip rate using an OVSF code c_(ch,SF,1), i.e., (SF_(E-DPCCH), 1), tomaintain orthogonality with other physical channels. Thereafter, theoutput of the multiplier 406 is multiplied by a channel gain β_(ec) in amultiplier 408. The E-DPCCH control information multiplied by thechannel gain β_(sc) is input to the summer 426.

Packet data provided from the EUDCH packet transmitter 404 is convertedinto a complex symbol stream I+jQ, and then delivered to a multiplier446 and a multiplier 416 as I and Q channel components, respectively.The multiplier 446 spreads the packet data into an I channel componentof a modulation symbol with an OVSF code C_(ed2) at a chip rate. Theoutput of the multiplier 446 is multiplied by a channel gain β_(ed2) ina multiplier 448. The summer 426 forms an I channel by summing up theDPDCH data, the E-DPCCH control information, and the E-DPDCH2 data.

Control information on the DPCCH is spread in a multiplier 428 at a chiprate using an OVSF code (256, 0), i.e., c_(ch,256,0), and thenmultiplied by a channel gain β_(c) in a multiplier 430. The DPCCHcontrol information multiplied by the channel gain β_(c), is input to asummer 436.

Control information on the HS-DPCCH is spread in a multiplier 432 usingan OVSF code (256, 64), i.e., c_(ch,256,64), at a chip rate, and thenmultiplied by a channel gain β_(hs) in a multiplier 434.

A Q channel component of a EUDCH packet data modulation symbol providedfrom the EUDCH packet transmitter 404 is spread in a multiplier 416 withan OVSF code C_(ed1) at a chip rate. The output of the multiplier 416 ismultiplied by a channel gain β_(ed1) in a multiplier 418. The summer 436forms a Q channel by summing up the DPCCH control information, theHS-DPCCH control information, and the E-DPDCH1 data. The output of thesummer 436 is multiplied by an imaginary number in a multiplier 438, andthen delivered to a summer 440.

The summer 440 forms one complex symbol stream by summing up the outputof the summer 426 and the output of the multiplier 438, and delivers thecomplex symbol stream to a multiplier 450. The multiplier 450 scramblesthe complex symbol stream using a scrambling code S_(dpch,1). Thescrambled complex symbol stream is converted into a pulse signal by apulse shaping filter 452, and then delivered to the Node B via anantenna 456 through an RF module 454.

FIG. 5 is a diagram illustrating a comparison between physical channelsin terms of a PAPR reduction effect by FIG. 4.

In FIG. 5, reference numeral 40 represents the case where a methodproposed by the present invention is used, and reference numerals 41 and42 represent the cases where different OVSF codes or different I/Qchannels are allocated for an E-DPCCH. Herein, the PAPR result has beenobtained through simulation using the transmission pulse shaping filter452 and the scrambling code, specified in the Rel-5 WCDMA standard, andthe channel gain P is generally set under discussion of the EUDCHtechnique.

Referring to FIG. 5, the case 40 proposed by the present invention issuperior to the case 41 in terms of a PAPR reduction effect by about 0.7dB. In addition, the case 40 proposed by the present invention issuperior to the case 42 in terms of a PAPR reduction effect by about0.12 dB. That is, the proposed OVSF code and I/Q channel allocationmethod for the E-DPCCH and the E-DPDCH can achieve a relatively lowPAPR.

A description will now be made of an OVSF code and I/Q channelallocation method for an E-DPCCH and an E-DPDCH consideringtransmission/non-transmission of an HS-DPCCH when compatibility with theexisting Rel-5 standard is maintained and at least one DPDCH istransmitted, according to sixth to ninth embodiments.

Sixth Embodiment

1. One or More DPDCHs being Transmittable and HS-DPCCH being notTransmitted

A method of allocating I/Q channels and OVSF codes for a DPCCH and aDPDCH according to the current standard are illustrated in Table 1.TABLE 1 Channel Allocation DPCCH (Q, 256, 0) DPDCH (I, SF, SF/4)

That is, a DPCCH channel is transmitted on a Q channel using an OVSFcode (256, 0), and a DPDCH can be allocated to an I channel with an OVSFcode (SF_(DPDCH), SF_(DPDCH)/4). Here, 4, 8, 16, 32, 64, 128, 256 and512 are available for the SF_(DPDCH).

A method of allocating I/Q channels and OVSF codes for an E-DPCCH andE-DPDCHs in the present invention considering compatibility with thecurrent standard of Table 1 is illustrated in Table 2. TABLE 2 ChannelAllocation E-DPCCH (I, SF_(E-DPCCH), 1) E-DPDCH1, E-DPDCH2, (Q, SF,SF/4), (I, 4, 3) E-DPDCH3, E-DPDCH4, (Q, 4, 3), (I, 4, 2) E-DPDCH5 (Q,4, 2)

Here, 8, 16, 32, 64, 128 and 256 are available for the SF_(E-DPCCH) forthe E-DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available forthe SF_(E-DPDCH) for the E-DPDCHs.

As illustrated in Table 2, if a maximum of 5 E-DPDCH channels can betransmitted and SF=4 is applied to an E-DPDCH 1, the E-DPDCH 1 istransmitted on a Q channel using an OVSF code (4, 1), and an E-DPDCH2 istransmitted on an I channel with an OVSF code (4, 3). In addition, anE-DPDCH3 is transmitted on a Q channel using an OVSF code (4, 3), and anE-DPDCH4 is transmitted on the I channel using an OVSF code (4, 2).Finally, an E-DPDCH5 is transmitted on the Q channel using an OVSF code(4, 2).

2. One or More DPDCHs being Transmittable and HS-DPCCH being Transmitted

A method of allocating I/Q channels and OVSF codes for a DPCCH, a DPDCH,and an HS-DPCCH according to the current standard are illustrated inTable 3. TABLE 3 Channel Allocation DPCCH (Q, 256, 0) DPDCH (I, SF,SF/4) HS-DPCCH (Q,.256, 64)

A method of allocating I/Q channels and OVSF codes for an E-DPCCH andE-DPDCHs in the present invention considering compatibility with thecurrent standard of Table 3 is illustrated in Table 4. TABLE 4 ChannelAllocation E-DPCCH (I, SF_(E-DPCCH), 1) E-DPDCH1, E-DPDCH2, (Q, SF,SF/4 + SF/2), (I, 4, 3) E-DPDCH3, E-DPDCH4 (Q, 4, 2), (I, 4, 2)

Here, 8, 16, 32, 64, 128 and 256 are available for the SF_(E-DPCCH) forthe E-DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available forthe SF_(E-DPDCH) for the E-DPDCHs.

In this case, if a maximum of 4 E-DPDCH channels can be transmitted andSF_(E-DPDCH)=4 is used, an E-DPDCH1 and an E-DPDCH2 are allocated (Q, 4,3) and (I, 4, 3), respectively. An E-DPDCH3 is transmitted on a Qchannel using an OVSF code (4, 2), and an E-DPDCH4 is transmitted on anI channel using an OVSF code (4, 2).

3. A Maximum of 2 DPDCHs being Transmittable and HS-DPCCH being notTransmitted A method of allocating I/Q channels and OVSF codes for aDPCCH and DPDCHs according to the current standard is illustrated inTable 5. TABLE 5 Channel Allocation DPCCH (Q, 256, 0) DPDCH1, DPDCH2 (I,SF, SF/4), (Q, 4, 1)

A method of allocating I/Q channels and OVSF codes for an E-DPCCH andE-DPDCHs in the present invention considering compatibility with thecurrent standard of Table 5 is illustrated in Table 6. TABLE 6 ChannelAllocation E-DPCCH (I, SF _(E-DPCCH), 1) E-DPDCH1, E-DPDCH2, (Q, SF,SF/4 + SF/2), (I, 4, 3) E-DPDCH3, E-DPDCH4 (Q, 4, 2), (I, 4, 2)

Here, 8, 16, 32, 64, 128 and 256 are available for the SF_(E-DPCCH) forthe E-DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available forthe SF_(E-DPDCH) for the E-DPDCHs.

In this case, if a maximum of 4 E-DPDCH channels can be transmitted andSF_(E-DPDCH)=4 is used, an E-DPDCH1 and an E-DPDCH2 are transmittedusing (Q, 4, 3) and (I, 4, 3), respectively. An E-DPDCH3 is transmittedon a Q channel using an OVSF code (4, 2), and an E-DPDCH4 is transmittedon an I channel using an OVSF code (4, 2).

4. A Maximum of 2 DPDCHs being Transmittable and HS-DPCCH beingTransmitted

A method of allocating I/Q channels and OVSF codes for a DPCCH, a DPDCHand an HS-DPCCH according to the current standard is illustrated inTable 7. TABLE 7 Channel Allocation DPCCH (Q, 256, 0) DPDCH (I, SF,SF/4) HS-DPCCH (Q, 256, 64)

A method of allocating I/Q channels and OVSF codes for an E-DPCCH andE-DPDCHs in the present invention considering compatibility with thecurrent standard of Table 7 is illustrated in Table 8. TABLE 8 ChannelAllocation E-DPCCH (Q, SF_(E-DPCCH), SF_(E-DPCCH)/8) E-DPDCH1, E-DPDCH2,(I, SF, SF/4 + SF/2), (Q, 4, 8) E-DPDCH3, E-DPDCH4 (I, 4, 2), (Q, 4, 2)

Here, 64, 128 and 256 are available for the SF_(E-DPCCH) for theE-DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available for theSF_(E-DPDCH) for the E-DPDCHs.

In this case, if a maximum of 4 E-DPDCH channels can be transmitted andSF=4 is used, an E-DPDCH1 and an E-DPDCH2 are allocated (I, 4, 3) and(Q, 4, 3), respectively. An E-DPDCH3 is transmitted on an I channelusing an OVSF code (4, 2), and an E-DPDCH4 is transmitted on a Q channelusing an OVSF code (4, 2).

5. A Maximum of 3 DPDCHs being Transmittable and HS-DPCCH being notTransmitted

A method of allocating I/Q channels and OVSF codes for a DPCCH andDPDCHs according to the current standard is illustrated in Table 9.TABLE 9 Channel Allocation DPCCH (Q, 256, 0) DPDCH1, DPDCH2, (I, SF,SF/4), (Q, 4, 1) DPDCH3 (I, 4, 3)

A method of allocating I/Q channels and OVSF codes for an E-DPCCH andE-DPDCHs in the present invention considering compatibility with thecurrent standard of Table 9 is illustrated in Table 10. TABLE 10 ChannelAllocation E-DPCCH (I, SF_(E-DPCCH), 1) E-DPDCHl, E-DPDCH2, (Q, SF,SF/4 + SF/2), (I, 4, 2) E-DPDCH3 (Q, 4, 2)

Here, 8, 16, 32, 64, 128 and 256 are available for the SF_(E-DPCCH) forthe E-DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available forthe SF_(E-DPDCH) for the E-DPDCHs.

In this case, if a maximum of 3 E-DPDCH channels can be transmitted andSF=4 is used, an E-DPDCH 1 is transmitted on a Q channel using an OVSFcode (4, 3). An E-DPDCH2 is transmitted on an I channel using an OVSFcode (4, 2), and an E-DPDCH3 is transmitted on the Q channel using anOVSF code (4, 2).

6. A Maximum of 3 DPDCHs being Transmittable and HS-DPCCH beingTransmitted

A method of allocating I/Q channels and OVSF codes for a DPCCH, DPDCHsand an HS-DPCCH according to the current standard is illustrated inTable 11. TABLE 11 Channel Allocation DPCCH (Q, 256, 0) DPDCH1, DPDCH2,(I, SF, SF/4), (Q, 4, 1) DPDCH3 (I, 4, 3) HS-DPCCH (Q, 256, 32)

A method of allocating I/Q channels and OVSF codes for an E-DPCCH andE-DPDCHs in the present invention considering compatibility with thecurrent standard of Table 11 is illustrated in Table 12. TABLE 12Channel Allocation E-DPCCH (I, SF_(E-DPCCH), 1) E-DPDCH1, E-DPDCH2, (Q,SF, SF/4 + SF/2), (I, 4, 2) E-DPDCH3 (Q, 4, 2)

Here, 8, 16, 32, 64, 128 and 256 are available for the SF_(E-DPCCH) forthe E-DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available forthe SF_(E-DPDCH) for the E-DPDCHs.

In this case, if a maximum of 3 E-DPDCH channels can be transmitted andSF=4 is used, an E-DPDCH1 is transmitted on a Q channel using an OVSFcode (4, 3). An E-DPDCH2 is transmitted on an I channel using an OVSFcode (4, 2), and an E-DPDCH3 is transmitted on the Q channel using anOVSF code (4, 2).

7. A Maximum of 4 DPDCHs being Transmittable and HS-DPCCH being notTransmitted

A method of allocating I/Q channels and OVSF codes for a DPCCH andDPDCHs according to the current standard is illustrated in Table 13.TABLE 13 Channel Allocation DPCCH (Q, 256, 0) DPDCH1, DPDCH2, (I, SF,SF/4), (Q, 4, 1) DPDCH3, DPDCH4 (I, 4, 3), (Q, 4, 3)

A method of allocating I/Q channels and OVSF codes for an E-DPCCH andE-DPDCHs in the present invention considering compatibility with thecurrent standard of Table 13 is illustrated in Table 14. TABLE 14Channel Allocation E-DPCCH (I, SF_(E-DPCCH), 1) E-DPDCH1, E-DPDCH2 (I,SF, SF/2), (Q, 4, 2)

Here, 8, 16, 32, 64, 128 and 256 are available for the SF_(E-DPCCH) forthe E-DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available forthe SF_(E-DPDCH) for the E-DPDCHs.

In this case, if a maximum of 2 E-DPDCH channels can be transmitted andSF=4 is used, an E-DPDCH1 is transmitted on an I channel using an OVSFcode (4, 2) and an E-DPDCH2 is transmitted on a Q channel using an OVSFcode (4, 2).

8. A Maximum of 4 DPDCHs being Transmittable and HS-DPCCH beingTransmitted

A method of allocating I/Q channels and OVSF codes for a DPCCH andDPDCHs according to the current standard is illustrated in Table 15.TABLE 15 Channel Allocation DPCCH (Q, 256, 0) DPDCH1, DPDCH2, (I, SF,SF/4), (Q, 4, 1) DPDCH3, DPDCH4 (I, 4, 3), (Q, 4, 3) HS-DPCCH (I, 256,1)

A method of allocating I/Q channels and OVSF codes for an E-DPCCH andE-DPDCHs in the present invention considering compatibility with thecurrent standard of Table 15 is illustrated in Table 16. TABLE 16Channel Allocation E-DPCCH (Q, SF_(E-DPCCH), SF_(E-DPCCH)/8) E-DPDCH1,E-DPDCH2 (I, SF, SF/2), (Q, 4, 2)

Here, 64, 128 and 256 are available for the SF_(E-DPCCH) for theE-DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available for theSF_(E-DPDCH) for the E-DPDCHs.

In this case, if a maximum of 2 E-DPDCH channels can be transmitted andSF=4 is used, an E-DPDCH1 is transmitted on an I channel using an OVSFcode (4, 2) and an E-DPDCH2 is transmitted on a Q channel using an OVSFcode (4, 2).

9. A Maximum of 5 DPDCHs being Transmittable and HS-DPCCH being notTransmitted

A method of allocating I/Q channels and OVSF codes for a DPCCH andDPDCHs according to the current standard is illustrated in Table 17.TABLE 17 Channel Allocation DPCCH (Q, 256, 0) DPDCH1, DPDCH2, (I, SF,SF/4), (Q, 4, 1) DPDCH3, DPDCH4, (I, 4, 3), (Q, 4, 3) DPDCH5 (I, 4, 2)

A method of allocating I/Q channels and OVSF codes for an E-DPCCH andE-DPDCHs in the present invention considering compatibility with thecurrent standard of Table 17 is illustrated in Table 18. TABLE 18Channel Allocation E-DPCCH (I, SF_(E-DPCCH), 1) E-DPDCH1 (Q, SF, SF/2)

Here, 8, 16, 32, 64, 128 and 256 are available for the SF_(E-DPCCH) forthe E-DPCCH, and 8, 16, 32, 64, 128, 256 and 512 are available for theSF_(E-DPDCH) for the E-DPDCHs. A maximum of only one E-DPDCH can betransmitted. An E-DPDCH1 is transmitted on a Q channel using an OVSFcode (4, 2).

10. A Maximum of 5 DPDCHs being Transmittable and HS-DPCCH beingTransmitted

A method of allocating I/Q channels and OVSF codes for a DPCCH andDPDCHs according to the current standard is illustrated in Table 19.TABLE 19 Channel Allocation DPCCH (Q, 256, 0) DPDCH1, DPDCH2, (I, SF,SF/4), (Q, 4, 1) DPDCH3, DPDCH4, (I, 4, 3), (Q, 4, 3) DPDCH5 (I, 4, 2)HS-DPCCH (Q, 256, 32)

A method of allocating I/Q channels and OVSF codes for an E-DPCCH andE-DPDCHs in the present invention considering compatibility with thecurrent standard of Table 19 is illustrated in Table 20. TABLE 20Channel Allocation E-DPCCH (I, SF_(E-DPCCH), 1) E-DPDCH1, E-DPDCH2 (Q,SF, SF/2)

Here, 8, 16, 32, 64, 128 and 256 are available for the SF_(E-DPCCH) forthe E-DPCCH, and a maximum of only one E-DPDCH can be transmitted. AnE-DPDCH1 is transmitted on a Q channel using an OVSF code (4, 2).

Seventh Embodiment

Compared with the sixth embodiment, a seventh embodiment presents anallocation rule which is similar in packet back-off required in an RFpower amplifier but simpler in implementation. A method of allocatingI/Q channels and OVSF codes for an E-DPCCH and E-DPDCHs is determinedbased on the maximum number of transmittable DPDCHs andtransmission/non-transmission of an HS-DPCCH, and a basic rule thereofis as follows:

E-DPCCH: If the maximum number of transmittable DPDCHs is 2 or 4 and anHS-DPCCH is allocated (I, 256, 1), it uses (Q, SF_(E-DPCCH),SF_(E-DPCCH)/8) and in other cases, it uses (I, SF_(E-DPCCH), 1).

E-DPDCH: When several DPDCH channels are transmitted, the DPDCHs useOVSF codes in order of (I, 4, 1), (Q, 4, 1), (I, 4, 3), (Q, 4, 3), (I,4, 2) and (Q, 4, 2) according to a data rate. Therefore, the E-DPDCHsadditionally use the remaining codes except the codes set for DPDCHtransmission among the six codes in the arranged order according to aEUDCH packet data rate.

In a stand-alone case where only EUDCH is transmitted, HSDPA uses anOVSF code (256, 1) on an I channel, and in a case where a DPDCH is setup, HSDPA follows the Rel-5 standard.

It is most preferable to allocate I/Q channels and OVSF codes for theE-DPCCH and E-DPDCHs in the foregoing manner in terms of a PAPR.

1. HS-DPCCH being not Set Up and EUDCH Stand-Alone

An E-DPCCH always uses (I, SF_(E-DPCCH), 1). Here, 8, 16, 32, 64, 128and 256 are available for the SF_(E-DPCCH).

As illustrated in Table 21, the E-DPDCHs are allocated I/Q channels andOVSF codes according to the maximum number of transmittable DPDCHs.TABLE 21 Max No of Max No of Transmittable Transmittable DPDCHs E-DPDCHsE-DPDCH Allocation Order 0 6 (I, SF, SF/4), (Q, 4, 1), (I, 4, 3), (Q, 4,3), (I, 4, 2), (Q, 4, 2) 1 5 (Q, SF, SF/4), (I, 4, 3), (Q, 4, 3), (I, 4,2), (Q, 4, 2) 2 4 (I, SF, SF/2 + SF/4), (Q, 4, 3), (I, 4, 2), (Q, 4, 2)3 3 (Q, SF, SF/2 + SF/4), (I, 4, 2) (Q, 4, 2) 4 2 (I, SF, SF/2), (Q, 4,2) 5 1 (Q, SF, SF/2)

In Table 21, 4, 8, 16, 32, 64, 128, 256 and 512 are available for theSF. In Table 21, if the maximum number of transmittable DPDCHs is 0,E-DPDCHs transmitting EUDCH data can use a maximum of 6 codes.

For example, when all of the six channels are used according to theEUDCH data rate, an E-DPDCH1 is transmitted on an I channel using anOVSF code (4, 1), and an E-DPDCH2 is transmitted on a Q channel using anOVSF code (4, 1). An E-DPDCH3 is transmitted on the I channel using anOVSF code (4, 3), and an E-DPDCH4 is transmitted on the Q channel usingan OVSF code (4, 3). An E-DPDCH5 is transmitted on the I channel usingan OVSF code (4, 2), and an E-DPDCH6 is transmitted on the Q channelusing an OVSF code (4, 2).

As another example, if the maximum number of transmittable DPDCHs is 4in Table 21, E-DPDCHs for transmitting EUDCH data can use a maximum of 2codes. For the E-DPDCHs, an E-DPDCH1 is transmitted on an I channelusing an OVSF code (SF, SF/2), and an additionally allocated E-DPDCH2 istransmitted on a Q channel using an OVSF code (4, 2).

2. A Maximum of 1 DPDCH being Transmittable and HS-DPCCH being Allocated(Q, 256, 64)

An E-DPCCH always uses (I, SF_(E-DPCCH), 1). Here, 8, 16, 32, 64, 128and 256 are available for the SF_(E-DPCCH).

The E-DPDCHs are sequentially allocated four OVSF codes (I, SF,SF/2+SF/4), (Q, 4, 3), (I, 4, 2) and (Q, 4, 2) according to a EUDCH datarate. Here, 4, 8, 16, 32, 64, 128, 256 and 512 are available for the SF.Because the HS-DPCCH is allocated (Q, 256, 64) on the Q channel, theOVSF code (4, 1) can be hardly used for an E-DPDCH.

3. A Maximum of 2 DPDCHs being Transmittable and HS-DPCCH being Set Up

As illustrated in Table 22, an E-DPCCH is allocated I/Q channels andOVSF codes according to the maximum number of transmittable DPDCHs.TABLE 22 Max No of Transmittable DPDCHs E-DPCCH Allocation 1, 3, 5 (I,SF_(E-DPCCH,) 1) 2, 4 (Q, SF_(E-DPCCH,) SF_(E-DPCCH)/8)

In this case, if the maximum number of transmittable DPDCHs is 2 or 4and an HS-DPCCH is allocated (I, 256, 1), an E-DPCCH uses (Q,SF_(E-DPCCH), SF_(E-DPCCH)/8). Here, 64, 128 and 256 are available forthe SF_(E-DPCCH).

However, the E-DPDCHs are allocated I/Q channels and OVSF codes asillustrated in Table 21 according to the maximum number of transmittableDPDCHs.

Eighth Embodiment

An eighth embodiment has a basic principle of first allocating anE-DPDCH to a Q channel for an OVSF code having the same index, andadditionally allocating an E-DPDCH to an I channel. In this case, codesfor the E-DPDCHs are determined according to the maximum number oftransmittable DPDCHs and transmission/non-transmission of an HS-DPCCH.

That is, according to the eighth embodiment, DPDCHs are first allocatedto an I channel and E-DPDCHs are first allocated to a Q channel, so thatthe numbers of DPDCHs and E-DPDCHs transmitted on the I/Q channels canbe equal to each other. In order words, when an HS-DPCCH is transmittedon the Q channel using an OVSF code (256, 64) or the number of theDPDCHs is smaller than the maximum number of transmittable DPDCHs, theeighth embodiment can prevent an excessive increase in PAPR due to thepreponderance of DPDCHs and E-DPDCHs over the I channel.

However, when the foregoing OVSF code and I/Q channel allocation rulefor E-DPDCHs is used, compared with a DPCCH using an OVSF code (256, 0)on a Q channel, an E-DPDCH is transmitted on an I channel using (SF, 1),thereby minimizing an increase in PAPR. Here, 4, 8, 16, 32, 64 and 128are available for the SF. In a stand-alone case, HSDPA uses an OVSF code(256, 1) on an I channel, and in a case where a DPDCH is set up, HSDPAfollows the Rel-5 standard. It is most preferable to allocate OVSF codesin the foregoing manner in terms of a PAPR.

1. HS-DPCCH being not Set Up and EUDCH Stand-Alone

E-DPDCHs are allocated I/Q channels and OVSF codes as illustrated inTable 23 according to the maximum number of transmittable DPDCHs. TABLE23 Max No of Max No of Transmittable Transmittable DPDCHs E-DPDCHsE-DPDCH Allocation Order 0 6 (Q, SF, SF/4), (I, 4, 1), (Q, 4, 3), (I, 4,3), (Q, 4, 2), (I, 4, 2) 1 5 (Q, SF, SF/4), (Q, 4, 3), (I, 4, 3), (Q, 4,2), (I, 4, 2) 2 4 (Q, SF, SF/2 + SF/4), (I, 4, 3), (Q, 4, 2), (I, 4, 2)3 3 (Q, SF, SF/2 + SF/4), (Q, 4, 2) (I, 4, 2) 4 2 (Q, SF, SF/2), (I, 4,2) 5 1 (I, SF, SF/2)

In Table 23, 4, 8, 16, 32, 64, 128, 256 and 512 are available for theSF. In Table 23, if the maximum number of transmittable DPDCHs is 0, amaximum of 6 E-DPDCH channels can be transmitted. In this case, OVSFcodes are used in order of (Q, SF, SF/4), (I, 4, 1), (Q, 4, 3), (I, 4,3), (Q, 4, 2) and (I, 4, 2) according to the number of E-DPDCH channelsbeing transmitted.

However, if the maximum number of transmittable DPDCHs is 1, a maximumof 5 codes can be used for E-DPDCH channels transmitting EUDCH data, sothat a maximum of 5 E-DPDCH channels can be transmitted. In this case,OVSF codes are used in order of (Q, SF, SF/4), (Q, 4, 3), (I, 4, 3), (Q,4, 2) and (I, 4, 2) according to the number of E-DPDCH channels beingtransmitted.

As another example, if the maximum number of transmittable DPDCHs is 4in Table 23, a maximum of 2 codes can be used for E-DPDCHs. In thiscase, when only one E-DPDCH is transmitted, the E-DPDCH is transmittedon a Q channel using an OVSF code (SF, SF/2), and an E-DPDCHadditionally allocated when necessary is transmitted on an I channelusing an OVSF code (4, 2).

2. A Maximum of 1 DPDCH being Transmittable and HS-DPCCH being Allocated(Q, 256, 64)

E-DPDCHs are sequentially allocated four OVSF codes (Q, SF, SF/2+SF/4),(I, 4, 3), (Q, 4, 2) and (I, 4, 2) according to a EUDCH data rate. Here,4, 8, 16, 32, 64, 128, 256 and 512 are available for the SF.

For example, when only one E-DPDCH is transmitted, the E-DPDCH istransmitted on a Q channel using an OVSF code (SF, SF/2+SF/4). This isto prevent an excessive increase in PAPR due to the preponderance ofphysical data channels over one of the I and Q channels. Therefore,DPDCHs are transmitted on the I channel and E-DPDCHs are transmitted onthe Q channel, so that the number of physical data channels transmittedon the I channel is equal to the number of physical data channelstransmitted on the Q channel, thereby preventing an increase in PAPR.

3. A Maximum of 2 DPDCHs being Transmittable and HS-DPCCH being Set Up

The same code allocation rule as that illustrated in Table 23 is used.

Ninth Embodiment

When several E-DPDCH physical channels are transmitted, SF=2 OVSF codesare used for E-DPDCHs exceptionally only in the following case in orderto further reduce a PAPR.

For example, when (I, 4, 3) and (I, 4, 2) are simultaneously allocatedto E-DPDCHs for multicode transmission on the E-DPDCHs, the E-DPDCHs aretransmitted using (I, 2, 1) instead of the foregoing two codes. That is,for the case where E-DPDCHs are transmitted on the I channel using bothof the OVSF codes (4, 3) and (4, 2), the E-DPDCHs are transmitted on theI channel using the OVSF code (2, 1).

Likewise, for the case where OVSF codes (4, 3) and (4, 2) aresimultaneously allocated to E-DPDCHs on a Q channel, the E-DPDCHs aretransmitted on the Q channel using an OVSF code (2, 1). That is, theE-DPDCHs are transmitted using (Q, 2, 1).

The following tenth embodiment proposes a method of additionally usingpossible codes generated from an OVSF code (4, 1), including a Q channelOVSF code (256, 64) used by an HS-DPCCH channel, for E-DPDCHs. Inaddition, the tenth embodiment proposes a method of additionally usingcodes allocated to DPDCHs, for E-DPDCHs.

Tenth Embodiment

An OVSF code (Q, 256, 64) used for an HS-DPCCH is used for an additionalE-DPDCH. That is, the tenth embodiment allows an HS-DPCCH to use an OVSFcode (256, 32) on a Q channel, thereby guaranteeing a EUDCH data rate.In this embodiment, OVSF code and I/Q channel allocation methods forE-DPDCHs are summarized as follows.

1. Two or Less E-DPDCH Channels being Transmitted

The methods proposed in the first to fifth embodiments are used.

2. Three E-DPDCH Channels being Transmitted

An E-DPDCH1 and an E-DPDCH2 are allocated to I and Q channels,respectively, using an OVSF code (2, 1).

An E-DPDCH3 is allocated to the Q channel using an OVSF code (4, 1).

In this case, data transmitted over the E-DPDCH3 undergoes QPSKmodulation.

In addition, methods of using OVSF codes allocated to DPDCHs, forE-DPDCHs, are as follows.

1. Three or Less E-DPDCH Channels being Transmitted

The methods proposed in the sixth to ninth embodiments are used.

2. Four or Less E-DPDCH Channels being Transmitted When no DPDCH istransmitted, a fourth E-DPDCH is transmitted on an I channel using anOVSF code (4, 1).

[Effect of the Invention]

As described above, the present invention proposes an OVSF code and I/Qchannel allocation method optimized for E-DPDCHs and an E-DPCCH forEUDCH service, while maintaining backward compatibility with DPDCHs anda DPCCH which are uplink physical channels, in a method for allocatingOVSF codes and I/Q channels to uplink physical channels. In addition,the present invention proposes an HS-DPCCH channel and an OVSF codewhich are different from those defined in the existing Rel-5 standard inorder to increase a maximum EUDCH data rate, and an OVSF code and I/Qchannel allocation method optimized for E-DPDCHs and an E-DPCCH for theEUDCH service for the foregoing case.

Therefore, the present invention can minimize a PARP increase duringpacket data transmission for the EUDCH service and minimize atransmission error of EUDCH packet data, thereby contributing to anincrease in EUDCH service capacity. While the invention has been shownand described with reference to a certain preferred embodiment thereof,it will be understood by those skilled in the art that various changesin form and details may be made therein without departing from thespirit and scope of the invention as defined by the appended claims.

1. A method for supporting an enhanced packet service in a mobilecommunication system, the method comprising the steps of: allocating adata channel for transmitting enhanced packet data to a quadrature-phase(Q) channel considering the maximum number of transmittable uplinkphysical channels; and additionally allocating a data channel fortransmitting enhanced packet data to an in-phase (I) channel toguarantee a data rate of the enhanced packet data.
 2. The method ofclaim 1, wherein when a high speed packet service is supported, a datachannel for transmitting enhanced packet data is allocated to the Ichannel considering the maximum number of transmittable uplink physicalchannels.
 3. The method of claim 1, wherein when a high speed packetservice is supported, a data channel for transmitting enhanced packetdata is additionally allocated to the Q channel to guarantee a data rateof the enhanced packet data.
 4. The method of claim 1, wherein the datachannel for transmitting the enhanced packet data is allocated anOrthogonal Variable Spreading Factor (OVSF) code (SF, SF/2).
 5. Themethod of claim 4, wherein 2, 4, 8, 16, 32, 64, 128 and 256 areavailable for a spreading factor of the data channel.
 6. The method ofclaim 1, wherein an enhanced control channel for transmitting controlinformation related to the data channel for transmitting the enhancedpacket data is allocated an OVSF code (SF, 1) on the I channel.
 7. Themethod of claim 6, wherein 8, 16, 32, 64, 128 and 256 are available fora spreading factor of the enhanced control channel.
 8. A method fortransmitting packet data in a mobile communication system, the methodcomprising the steps of: generating a dedicated physical control channel(DPCCH) using an Orthogonal Variable Spreading Factor (OVSF) code (256,0) and a quadrature-phase (Q) channel; generating a dedicated physicaldata channel (DPDCH) using an OVSF code (SF_(DPDCH), SF_(DPDCH)/4) andan in-phase (I) channel, where SF_(DPDCH) denotes a spreading factor ofthe DPDCH; generating an E-DPCCH using an OVSF code (SF_(E-DPCCH), 1)and the I channel, where SF_(E-DPCCH) denotes a spreading factor of anOVSF code to be allocated to a dedicated control channel (E-DPCCH) forsupporting transmission of enhanced uplink packet data; and generatingan E-DPDCH using an OVSF code (SF_(E-DPDCH), SF_(E-DPDCH)/2) and the Qchannel, where SF_(E-DPDCH) denotes a spreading factor of an OVSF codeto be allocated to a dedicated data channel (E-DPDCH) for supportingtransmission of the enhanced uplink packet data.
 9. The method of claim8, further comprising the step of, if SF_(E-DPDCH) is 4 and two E-DPDCHsare simultaneously transmitted, simultaneously generating an E-DPDCH1and an E-DPDCH2 which are spread with an OVSF code (4, 2) on the Ichannel and the Q channel, respectively.
 10. The method of claim 8,further comprising the step of, if SF_(E-DPDCH) is 2 and two E-DPDCHsare simultaneously transmitted, generating an E-DPDCH1 and an E-DPDCH2which are spread with an OVSF code (2, 1) on the I channel and the Qchannel, respectively.
 11. The method of claim 8, further comprising thestep of, if SF_(E-DPDCH) is 2 and one E-DPDCH is transmitted, generatingan E-DPDCH which is spread with an OVSF code (2, 1) on the Q channel.12. The method of claim 8, wherein further comprising the step of, if anE-DPCCH is transmitted, generating an E-DPCCH which is spread with anOVSF code (256, 1) on the I channel.
 13. The method of claim 8, furthercomprising the step of, if a high speed downlink packet access (HSDPA)service is achieved, generating a high speed downlink physical channel(HS-DPCCH) using an OVSF code (256, 64) and the Q channel.
 14. Themethod of claim 8, further comprising the step of, if no DPDCH istransmitted, generating third and fourth E-DPCCHs using an OVSF code (4,1).
 15. The method of claim 14, further comprising the step of using anOVSF code (4, 1) and the I channel for the third E-DPCCH and using anOVSF code (4, 1) and the Q channel for the fourth E-DPCCH.
 16. Anapparatus for transmitting uplink packet data in a mobile communicationsystem supporting transmission of enhanced uplink packet data, theapparatus comprising: a transmission controller for determining thenumber of enhanced uplink data channels considering the maximum numberof transmittable dedicated physical channels, and alternately allocatingan Orthogonal Variable Spreading Factor (OVSF) code (SF, SF/2) to atleast one enhanced uplink data channels on a quadrature-phase (Q)channel and an in-phase (I) channel according to a data rate of theenhanced packet data; and a transmitter for alternately generatingenhanced data channels on the Q channel and the I channel according tothe number of enhanced uplink data channels, determined by thetransmission controller, spreading the packet data according to the OVSFcode, and transmitting the spread packet data.
 17. The apparatus ofclaim 16, wherein the transmission controller allocates an I channel andan OVSF code (SF, 1) to an enhanced uplink control channel fortransmitting control information related to the enhanced uplink datachannel.
 18. The apparatus of claim 16, wherein 2, 4, 8, 16, 32, 64, 128and 256 are available for a spreading factor of the enhanced uplink datachannel.
 19. The apparatus of claim 16, wherein 8, 16, 32, 64, 128 and256 are available for a spreading factor for the enhanced uplink controlchannel.
 20. A method for transmitting data in a mobile communicationsystem supporting transmission of uplink packet data, the methodcomprising the steps of: allocating an orthogonal code considering adata rate for transmission of the uplink packet data, and spreading thepacket data using the orthogonal code; summing up the spread packet datasignal and a signal spread with another OVSF code; and transmitting thesummed spread signal through an antenna; wherein if a dedicated physicalchannel (DPDCH) and a dedicated physical channel (HS-DPCCH) for a highspeed downlink packet are not set up, an orthogonal code (SF_(E-DPDCH),SF_(E-DPDCH)/4) for an in-phase (I) channel is allocated fortransmission of the uplink packet data, where SF_(E-DPDCH) denotes aspreading factor.
 21. The method of claim 20, wherein the SF_(E-DPDCH)is one of 4, 8, 16, 32, 64, 128, 256 and
 512. 22. The method of claim20, wherein when the SF_(E-DPDCH) is 4 and the data rate cannot besatisfied, an orthogonal code (2, 1) for the I channel is allocated. 23.The method of claim 20, wherein when two orthogonal codes are allocatedfor transmission of the packet data, an orthogonal code (2, 1) for the Ichannel and an orthogonal code (2, 1) for the Q channel are allocated.24. The method of claim 20, wherein when four orthogonal codes areallocated for transmission of the packet data, orthogonal code (2, 1)for the I and Q channels and orthogonal code (4, 1) for the I and Qchannels are allocated.
 25. A method for transmitting data in a mobilecommunication system supporting transmission of uplink packet data, themethod comprising the steps of: allocating an orthogonal codeconsidering a data rate for transmission of the uplink packet data, andspreading the packet data using the orthogonal code; summing up thespread packet data signal and a signal spread with another orthogonalcode; and transmitting the summed spread signal through an antenna;wherein if no dedicated physical channel (HS-DPCCH) for a high speeddownlink packet is set up, an orthogonal code (SF_(E-DPDCH),SF_(E-DPDCH)/4) for a quadrature-phase (Q) channel is allocated fortransmission of the uplink packet data, where SF_(E-DPDCH) denotes aspreading factor.
 26. The method of claim 25, wherein the SF_(E-DPDCH)is one of 4, 8, 16, 32, 64, 128, 256 and
 512. 27. The method of claim25, wherein if the SF_(E-DPDCH)=4 and the data rate cannot be satisfied,an orthogonal code (2, 1) for the Q channel is allocated.
 28. The methodof claim 25, wherein when two orthogonal codes are allocated for thepacket data, an orthogonal code (2, 1) for the Q channel and anorthogonal code (2, 1) for the I channel are allocated.
 29. The methodof claim 25, wherein when four orthogonal codes are allocated for thepacket data, an orthogonal code (2, 1) for the Q and I channels and anorthogonal code (4, 1) for the Q and I channels are allocated.
 30. Amethod for transmitting data in a mobile communication system supportingtransmission of uplink packet data, the method comprising the steps of:allocating an orthogonal code considering a data rate for transmissionof the uplink packet data, and spreading the packet data using theorthogonal code; summing up the spread packet data signal and a signalspread with another orthogonal code; and transmitting the summed spreadsignal through an antenna; wherein when a dedicated physical channel(HS-DPCCH) for a high speed downlink packet is set up, one of orthogonalcodes (SF_(E-DPCCH), 1) to (SF_(E-DPCCH), SF_(E-DPCCH)/8) for aquadrature-phase (Q) channel is selected and allocated to a controlchannel for transmission of the uplink packet data, where SF_(E-DPDCH)denotes a spreading factor.
 31. The method of claim 30, wherein theSF_(E-DPCCH) is one of 8, 16, 32, 64, 128, 256 and
 512. 32. A method fortransmitting data in a mobile communication system supportingtransmission of uplink packet data, the method comprising the steps of:allocating an orthogonal code considering a data rate for transmissionof the uplink packet data, and spreading the packet data using theorthogonal code; summing up the spread packet data and a signal spreadwith another orthogonal code; and transmitting the summed spread signalthrough an antenna; wherein if there is no dedicated physical channel(DPDCH), one of orthogonal codes (SF_(E-DPCCH), 1) to (SF_(E-DPCCH),SF_(E-DPCCH)/8) for a quadrature-phase (Q) channel is selectedregardless of a dedicated physical channel (HS-DPCCH) for a high speeddownlink packet and allocated to a control channel for transmission ofthe uplink packet data, where SF_(E-DPDCH) denotes a spreading factor.33. A method for transmitting packet data in a mobile communicationsystem, the method comprising the steps of: generating a dedicatedphysical control channel (DPCCH) using an Orthogonal Variable SpreadingFactor (OVSF) code (256, 0) and a quadrature-phase (Q) channel;generating a dedicated physical data channel (DPDCH) using an OVSF code(SF_(DPDCH), SF_(DPDCH)/4) and an in-phase (I) channel, where SF_(DPDCH)denotes a spreading factor of the DPDCH; generating an E-DPCCH using anOVSF code (SF_(E-DPCCH), 1) and the I channel, where SF_(E-DPCCH)denotes a spreading factor of an OVSF code to be allocated to adedicated control channel (E-DPCCH) for supporting transmission ofenhanced uplink packet data; and allocating an OVSF code (SF_(E-DPDCH),SF_(E-DPDCH)/2) for an E-DPDCH, where SF_(E-DPDCH) denotes a spreadingfactor of an OVSF code to be allocated to a dedicated data channel(E-DPDCH) for supporting transmission of the enhanced uplink packetdata; wherein if a high speed downlink physical channel (HS-DPCCH) isset up, an E-DPCCH is generated using the I channel, and if the HS-DPCCHis not set up, an E-DPCCH is generated using the Q channel.
 34. Themethod of claim 33, further comprising the step of, if SF_(E-DPDCH) is 4and two E-DPDCHs are simultaneously transmitted, simultaneouslygenerating an E-DPDCH1 and an E-DPDCH2 which are spread with an OVSFcode (4, 2) on the I channel and the Q channel, respectively.
 35. Themethod of claim 33, further comprising the step of, if SF_(E-DPDCH) is 2and two E-DPDCHs are simultaneously transmitted, generating an E-DPDCH1and an E-DPDCH2 which are spread with an OVSF code (2, 1) on the Ichannel and the Q channel, respectively.
 36. The method of claim 33,further comprising the step of, if SF_(E-DPDCH) is 2 and one E-DPDCH istransmitted, generating an E-DPDCH which is spread with an OVSF code(2, 1) on the Q channel.
 37. The method of claim 33, further comprisingthe step of, if an E-DPCCH is transmitted, generating an E-DPCCH whichis spread with an OVSF code (256, 1) on the I channel.
 38. The method ofclaim 33, further comprising the step of, if a high speed downlinkpacket access (HSDPA) service is achieved, generating a high speeddownlink physical channel (HS-DPCCH) using an OVSF code (256, 64) andthe Q channel.
 39. The method of claim 33, further comprising the stepof, if no DPDCH is transmitted, generating third and fourth E-DPCCHsusing an OVSF code (4, 1).
 40. The method of claim 39, furthercomprising the step of generating the third E-DPCCH using an OVSF code(4, 1) and the I channel and generating the fourth E-DPCCH using an OVSFcode (4, 1) and the Q channel.